Junior Seau had concussions while playing in the National Football League. How many is a subject for discussion, and one former teammate provided an answer: 1,500.

Gary Plummer isn't a doctor; he is a 52-year-old former NFL linebacker. He played 15 years, including time in lower pro leagues. And he told the San Jose Mercury News he had 1,000 concussions during his career.

Seau died Wednesday of a self-inflicted gunshot wound. Police say he put a pistol to his heart and pulled the trigger in his home near San Diego.

It was the latest in a series of suicides by retired NFL players. Last year, former Chicago Bears safety Dave Duerson took his life while fighting depression that was linked to brain trauma caused by repeated blows to the head. Last month, former Atlanta Falcons safety Ray Easterling committed suicide after struggling with depression and dementia.

Plummer was a Seau teammate for four seasons with the San Diego Chargers, and he was among thousands who were left in shock and sorrow at word of Seau's death.

He based his concussion estimates, Plummer told the Mercury News, on information from more than a decade ago.

"In the 1990s, I did a concussion seminar," he said. "They said a Grade 3 concussion meant you were knocked out, and a Grade 1 meant you were seeing stars after a hit, which made me burst out in laughter. As a middle linebacker in the NFL, if you don't have five of these each game, you were inactive the next game.

"Junior played for 20 years. That's five concussions a game, easily. How many in his career then? That's over 1,500 concussions. I know that's startling, but I know it's true. I had over 1,000 in my 15 years. I felt the effects of it. I felt depression going on throughout my divorce. Junior went through it with his divorce."

While Plummer's math might be fuzzy, his experience and the experiences of other players lend credence to his words. The NFL is facing lawsuits regarding its attention, or lack of same, to concussions. Numerous former players saw their careers ended by head injuries, and others experience post-concussion syndrome, as Plummer does.

Other comments by Plummer:

— Seau was in crying need of help but was too proud to ask for it. As recently as a golf event earlier this month, Plummer says Seau was telling people he was fine. Other reports say he appeared OK at that golf event.

— The NFL must continue its efforts to evaluate and treat concussions, but the culture of playing through head injuries must be changed.

— Counseling should be made mandatory for treatment of concussions and post-concussion symptoms.

"When we're forced out, try to give us tools (for) what we're going to face," Plummer said. "I've talked to former teammates who've struggled mightily. Not just within a year of being out but several years. One guy felt he was wandering aimlessly.